Disclosed in the embodiments described in this application is an improved system for registering and conveying compiled sets of sheets.
In particular, there is disclosed an improved, low cost and simple system for compiling a set of documents in a registered manner and then conveying this compiled set toward an output station or toward any of various workstations for further finishing operations to be performed on the compiled set of documents.
Various types of registration and conveyance systems are known in the art. Many configurations in the Xerox DocuTech.RTM. family of multifunctional printers compile and register a set of documents in an output tray near the receiving mouth of the finisher apparatus. A gripper then squeezes and grabs a corner of the fully registered set and pulls the set along a conveyer toward the selected finishing station which may perform binding, stapling, or any similar finishing operation. Although this apparatus works well in most applications, it requires a complicated apparatus with a significant number of moving parts plus sensors to activate and deactivate the gripper apparatus with an appropriate amount of pressure that is sufficient to grip the compiled stack but not great enough to leave an imprint on the paper. In practice, a gripper-type mechanism limits the number of sheets that can be compiled since the gap between the gripper fingers effectively determines the depth of the pile that can be gripped.
It is also known in the art to compile and register a set of documents near the receiving mouth of a finishing apparatus and then to maintain the registration during conveyance by pushing the trailing edge of the compiled set by a registration stop or registration fingers located on a conveyance belt. Although relatively simple and without many moving parts, in an apparatus of this type, the top sheets of the compiled stack may fluff or otherwise slip out of registration. As a result, this type of conveyance apparatus also has an effective upper limit to the number of sheets that can effectively be conveyed in good registration.
It would be advantageous to have a reliable, low cost apparatus capable of reliably receiving a compiled stack of sheets and conveying the compiled sheets with good registration to the selected finishing station.